NOX Sensor Replacement - Star Learning?

[Ding009]

Good evening all,

Quick question tonight.

Due to the fault codes, and suggestion from MB, I understand the NOX sensor/s need replacing. MB suggest both, but only one is malfunctioning at present. From readin these forums, I understand it that once a NOX sensor or sensors has/have been replaced, the Star system is to be used to let the ECU learn the new sensors, and alighn with the software etc.

So my question is, if I got the right NOX sensors, and I installed them myself to save cost, would the car actually start before the Star system bit was done? Or would I need the Star system present at the point of completing the change? Just trying to understand how mobile the car would be after the Nox sensor swap?

Car is a 2015 220D CLS Shooting brake. X218.

I have also read somewhere that some NOX sensors are plug and play, so no Star involvement. Is that true, and if so which sensors?

Thank you

 

[Uncle Benz]

Now this is my understanding, and I’m happy to be contradicted…
There are “generation 1” and “generation 2” sensors. The gen 1 usually fail pretty quickly if the car gets the “dieselgate” software recall. The gen 2 sensors cope after the recall. There is a xentry proceedure for updating to gen 2, but honestly, I think it’s just an adaptation reset that most aftermarket scan tools can do. I do a lot of specialist Mercedes work for other garages near me, and I know for a fact that they’ve fitted gen 2 sensors with their tools and been fine. Any sensors you buy from mercedes now are gen 2. Gen 1 is discontinued. A word of advice though, go genuine on the part. Plenty of cheap junk out there, and they don’t last

 

[Ding009]

Thank you for the quick reply.

Yes I can see a big price difference when searching, and when the purse strings are tight it feels easy to go for the cheaper option, but have been there before on other parts.

Is there a way of knowing by the product code, or should it say in the description if it is Gen 2? is it the same part number? And when you say Genuine parts, do you literally mean MB products or do you feel the likes of recognised names (guessing at things like Bosch etc) would suffice?

Thanks again

 

[Uncle Benz]

I only buy them from Mercedes. That way you know it’s the latest type. Some of them are on Mercedes exchange program, where they effectively give you a discount if you return your old part. They will NOT voluntarily reveal this, so you must ask if an exchange part is available. Expect then the “dirty trick” response of “yes, but we only have the non-exchange part in stock”. Call their bluff and ask them to order one for you.

 

[mersum1es]

gen 2 sensors require software update AFAIK (control module comes with sensor)

 

[Ding009]

gen 2 sensors require software update AFAIK (control module comes with sensor)

Thank you. But would the car start without it? So if I did the swap on my drive, would the car start so it could be taken to the garage for the update to be done?

 

[Uncle Benz]

gen 2 sensors require software update AFAIK (control module comes with sensor)

I think that’s a line you have been spun to encourage you to book in for the dieselgate software update. The Gen 2 sensors will work on the old software. I’ve done it.

 

[Uncle Benz]

Thank you. But would the car start without it? So if I did the swap on my drive, would the car start so it could be taken to the garage for the update to be done?

Yes, it will start and run fine. You may still have the engine light on until the adaptations are reset and fault codes cleared